Casus belli

"Act of War" redirects here. For other uses, see Casus belli (disambiguation) and Acts of war (disambiguation).

A casus belli (from Latin casus belli 'occasion for war'; pl. casus belli) is an act or an event that either provokes or is used to justify a war.[1][2] A casus belli involves direct offenses or threats against the nation declaring the war, whereas a casus foederis involves offenses or threats against its ally—usually one bound by a mutual defense pact.[3][4] Either may be considered an act of war.[5] A declaration of war usually contains a description of the casus belli that has led the party in question to declare war on another party.

  1. ^ "casus belli". Lexico UK English Dictionary. Oxford University Press. Archived from the original on 2022-03-03.
  2. ^ "casus belli". Chambers 21st Century Dictionary. Allied Publishers. 2001. p. 219. ISBN 978-81-8424-329-1.
  3. ^ Bynkershoek, Cornelius van (2007). A Treatise on the Law of War. Lawbook Exchange. ISBN 978-1-58477-566-9.
  4. ^ Bynkershoek, Cornelius van (1995). On Questions of Public Law. William S. Hein & Company. ISBN 1-57588-258-2.
  5. ^ Bryan A. Garner (2001). A Dictionary of Modern Legal Usage. Oxford University Press. pp. 137–. ISBN 978-0-19-514236-5.